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The threatened Okaloosa darter ( Etheostoma okaloosae ) is found almost exclusively on the Eglin Air Force Base in the Choctawhatchee Bay watershed of Florida. Portions of this limited habitat are threatened with soil erosion, altered hydrology, and impaired water quality. In the present study, general water quality parameters (i.e., dissolved oxygen, specific conductance, pH, temperature, relative turbidity, and primary productivity) were characterized in East Turkey Creek, which is a body of water potentially impacted by treated wastewater sprayfields, and Long Creek, an adjacent reference stream that does not border the sprayfields. Water quality was assessed during a 30-day exposure using passive samplers for both non-polar and polar effluent parameters. Because the Okaloosa darter was listed as endangered at the time of sampling we chose a closely related species from the same creeks, the sailfin shiner ( Pteronotropis hypseleotris ) in which to measure metal body burdens. Additionally, fathead minnows ( Pimephales promelas ) were used for microarray analysis on gonad and liver tissues after 48 h exposures to water collected from the two creeks and brought into the laboratory. Waters from all sites, including reference sites, affected the expression of genes related to various biological processes including transcription and translation, cell cycle control, metabolism, and signaling pathways, suggesting that the sum of anthropogenic compounds in the site waters may cause a generalized stress response in both liver and testis, an effect that could be related to the generally low populations of the Okaloosa darter. Furthermore, effects of site waters on fish gene expression may be related to the impact of human activities other than the wastewater sprayfields, as nearby areas are closed to the public for military testing, training, and administrative activities and due to ordnance contamination.

Reduced habitat quality may be contributing to the decline of freshwater mussels in southeastern rivers. As part of an ongoing evaluation of the quality of freshwater mussel habitat in Gulf of Mexico coastal rivers, the Chipola River was assessed during 2006 and 2007. Sediment sam- ples were collected at 8 sites along the Chipola River on May 2 and 3, 2006, and analyzed for conta- minants and tested in the laboratory for toxicity to Hyalella azteca using 29 d exposures to solid- phase sediment and 96 h exposures to sediment porewater. In addition, benthic macroinvertebrate populations were sampled at each site. Using the sediment quality triad approach (chemistry, toxic- ity and in situ benthic assemblages) to assess habitat quality, 3 sites (1, 4 and 8) were shown to be impaired, with Site 4 being the most impaired site. H. azteca survival in porewater exposures was reduced, and trace elements were elevated in sediments at these sites; however, concentrations were not considered exceedingly high. Water quality samples collected did not violate the State of Florida's water quality standards. The lack of concordance among the test metrics (in situ benthic assemblages were not impaired) at these sites suggests marginal habitat impairment.

Water chemical analyses, porewater and whole sediment chemical analyses, and pore- water and whole sediment toxicity testing were performed as part of a combined effort between the US Fish and Wildlife Service and the US Geological Survey. These analyses were used to predict impaired stream sites that may impede a healthy natural riverine community. The analyses also revealed differences between sites that currently support and those that have ceased to support mus- sel populations. We estimated risk scores for the riverine community based on water and sediment characteristics. To identify and rank habitat in need of restoration, the risk estimation was derived by comparing collected data to water quality standards, sediment quality guidelines and toxicity test controls. High-risk scores often coincided with areas that no longer support historical freshwater mussel populations. Based on the data collected, factors thought to impede the existence of a natural riverine community included: sediment toxicity (porewater and whole sediment), sediment lead, sediment manganese, sediment ammonia, and low dissolved oxygen.

Choctawhatchee Bay is located in the western Florida panhandle. The system was originally oligohaline with input primarily from Choctawhatchee River which terminates at the east end of the bay. The Choctawhatchee Bay and River watershed has a drainage area of 5349 square miles in Florida and Alabama (NWFWMD, 1996). Historically, marine waters entered the bay via only periodic breakthroughs to the Gulf of Mexico. A permanent pass to the Gulf of Mexico was opened in 1929 at the west end of the bay (Livingston, 1987). Marine waters from the Gulf of Mexico flowed through the western pass and combined with the freshwaters from the Choctawhatchee River creating an estuary in transition. Choctawhatchee Bay has an east to west longitudinal axis that stretches 27 miles long, but is only 4 miles wide. Average depth of the bay is 22 ft (US Department of Commerce and NOAA, 1997). Choctawhatchee Bay has several small tributaries on the northern shore. Eglin Air Force Base occupies the majority of the immediate drainage basin on the northern shore. While the northern shore has experienced some development, the southern shore of Choctawhatchee Bay has been the site of an exponential increase in urbanized growth over the last few decades (US Department of Commerce and NOAA, 1997). Previous studies have identified high metal concentrations and low dissolved oxygen in Choctawhatchee Bay and adjoining bayous (Livingston, 1987). Some have speculated that the low dissolved oxygen concentrations result from the unique nature of Choctawhatchee Bay, particularly the dramatic convergence of fresh and marine waters (US Department of Commerce and NOAA, 1997). Choctawhatchee Bay is stratified via a halocline separating freshwater at the surface from marine waters at the bottom. The lack of mixing and gas exchange between the marine and fresh waters creates a large anoxic zone in the marine (bottom) bay layer, resulting in low biotic integrity (Livingston, 1987). The literature has identified areas of concern in Choctawhatchee Bay and distinguished possible problem sources (Livingston, 1987; US Department of Commerce and NOAA, 1997; NWFWMD, 1996). Reportedly, stormwater runoff and residential development were responsible for increased nutrient loading to the bay. It was further suggested that these nonpoint source inputs were exacerbating problems in the bayous where water quality was often lower (CBA, 1998). Other Edited by Bruce J. Richardson

The estrogenicity of a municipal wastewater effluent was monitored using the vitellogenin biomarker in adult male fathead minnows (Pimephales promelas). The variability in the expression of vitellogenin was evident among the monitoring periods. Significant (alphaor =0.05) increases in plasma vitellogenin concentrations were detected in March and December, but not in August or June. Additionally, the magnitude of expression was variable. Variability in the spatial scale was also evident during the March and June exposure months. Concurrent exposures in both the creek receiving the effluent from a wastewater treatment plant and an experimental wetland showed estrogenicity to be different with distance from the respective effluent inflow sites. March exposures showed estrogenicity to be somewhat persistent in the receiving creek (600 m), but to decrease rapidly within the experimental wetland (40 m). Results are discussed relative to the monitoring season, to the spatial distribution of the response in both receiving systems, and to possible causative factors contributing to the effluent estrogenicity.

Effluent toxicity is regularly assessed with Ceriodaphnia dubia short-term chronic and Vibrio fischeri toxicity tests. Condition factor and hemotocrit of fish have recently been used to assess fish health following exposure to xenoestrogens in complex municipal effluents. To assess the ability of a treatment wetland to reduce or remove toxicity of a municipal effluent, we compared C. dubia and V. fischeri bioassays to Pimephales promelas responses in situ. Final whole effluent was diverted to a constructed wetland and effluent samples were taken daily from four sites, at incremental distances from the inflow, for a 3-week study. Overlapping 7-day C. dubia tests and V. fischeri assays were conducted with samples from each wetland site concurrent with a 3-week fish exposure. C. dubia survival and fecundity were significantly (< 0.0001) reduced at the inflow, but steadily improved with distance from the inflow. Fish condition and hematocrit were lower (α < 0.05) at wetland sites closer to the inflow than other wetland sites and laboratory controls. However, effluent toxicity was not detected by V. fischeri bioassays. Our findings indicate that 7-day C. dubia bioassays were most sensitive to effluent toxicity and suggest that other bioassays should be used concurrent with V. fischeri assays for municipal effluent toxicity testing.

The toxicity and estrogenicity of a final treated municipal effluent was examined while flowing through a constructed wetland in north-central Texas, USA. Fish data were collected, and a baseline wetland characterization was performed to assess wetland treatment potential for these effluent properties. Vitellogenin (VTG), gonadosomatic index (GSI), hepatosomatic index (HSI), and secondary sexual characteristics were biomarkers used in fish models to assess aqueous estrogenicity. Biological indicators used to assess overall fish health included hematocrit and condition factor. Estrogenic nature of final sewage treatment works effluent was screened, concurrent with a three-week fish exposure, via gas chromatography/mass spectrometry for target estrogenic compounds, including 17β-estradiol, ethynylestradiol, bisphenol A, nonylphenolic compounds, phthalates, and DDT. The VTG in Pimephales promelas was measured after exposure at four sites in a treatment wetland and was significantly elevated (p < 0.0001) in fish exposed at the inflow site. The GSIs were significantly less (α = 0.001) at the inflow site. At wetland sites closest to the inflow, secondary sexual characteristics, tubercle numbers, and fatpad thickness were less (α = 0.0001) than in laboratory controls. The HSIs and density of male breeding stripes were not significantly different from those of laboratory controls. However, elevated HSIs were found at the inflow site. Hematocrit and condition factors were both less (α = 0.001) in effluent-exposed fish at wetland sites closer to the inflow than in control fish or fish further downstream.